The broad objective of this research is to gain further knowledge about behavioral and environmental factors in the regulation of activity of the autonomic nervous system in man. Currently, the major overall aim is to gather systematic data on feedback, behavioral, cognitive, and physiological variables related to the ability of human subjects to control their systolic blood pressure. The research builds on earlier findings in our laboratory that systolic and diastolic blood pressure can be modified using biofeedback and reward techniques. A constant-cuff pressure system is used to track median blood pressure and to give information to subjects on relative changes in pressure on each successive heart beat. In addition, other simultaneous variables are monitored, depending upon the study: heart rate, respiration, vasomotor activity, muscle tension, and skin temperature. A number of studies are proposed which attempt to refine and evaluate the feedback techniques and compare them with alternative methods of blood pressure control. The eventual goal is the effective application of the procedures as an approach to clinical research and treatment of essential hypertension. The specific aims are: (1) To compare the relative effectiveness of positive versus negative feedback with varying instructions, (2) To evaluate the effects of different amounts of feedback on each successive heart beat, (3) To evaluate the effects of different amounts of feedback averaged over different sets of heart beats, (4) To study the effects of alternative methods of blood pressure control (cognitive, physical relaxation and tension, alternative methods of feedback, blood pressure awareness training), and (5) To evaluate the "optimal" combination of blood pressure control procedures in a sample of persons with relatively high blood pressure.